My only issue is if they bring back a wimpy Nagash......that would p*ss me off something rotten. His history and lore demand so much, but GW have a horrible habit of badly nerfing rules for some characters so I'll just have to hope. The original Nagash fully pimped out was around 800pts......I would be happy to pay that much again to ensure he isn't nerfed.
As for Abhorash.....I'll be amazed if they bring him into the fray. He has kinda turned into VC's Chuck Norris, and even outside of VC plenty of players agree that he is possibly the most skilled warrior in existence. I can't seem them properly portraying this for fear of upsetting other players (like HE over Tyrion etc......who Abhorash would whup all over)
The flying chariot is easily Arkhan, that's what he rode back in the 4th edition and it would be great to see him back.
Would I like to see VC and TK brought back under the Undead umbrella.....no not really. Both armies have developed and moved forward to such an extent that they belong separate. It would be like bring all the Elves under one book. That said.....if they did do it under the leadership of an all powerful Nagash, well that I could certainly learn to live with.
His return is not wimpy. I hope you are pleased. He is the summoning master, and so much more, we all wanted IMO. Also I love the joining of the two armies again. Plus the lore has been amazing so far...
Long live our Master, Nagash Supreme Lord of the Undead!